This invention relates to absorbent bodies as used in products designed to absorb body exudates such as catamenial napkins and tampons, diapers, surgical sponges, wound dressings and the like. These products generally comprise an absorbent body enveloped by a material, at least a portion of which is permeable to body exudates. In the case of catamenial tampons, for example, the absorbent body is generally in a highly compressed form and in some circumstances may be used without the enveloping material. In the case of diapers and sanitary napkins, the absorbent body is generally in the form of a pad sandwiched between a facing sheet and a backing sheet, the latter of which may be impermeable to body exudates. Notwithstanding the particular configuration, it is, of course, desirable that the absorbent body have a relatively high absorbency per unit weight for the aqueous based body exudate fluids.
Most commonly, absorbent bodies for these products are made of highly porous batts of wood pulp fiber and generally meet the criteria for products of this nature in that wood pulp is absorbent, inexpensive and, in the form of loose batts, comfortable to the ultimate user. Nevertheless, in efforts to improve these absorbent products, the art is now replete with modifications of, and substitute materials for, wood pulp.
One such modified material is disclosed in U.S. Pat. No. 3,256,372 and is described therein as a product produced by chemically grafting, in a water slurry, hydrophilic polymer chains onto cellulose fibers such as wood pulp (this product, among others, hereinafter referred to as grafted cellulose). The wet fibers obtained from the slurry are then extruded into shaped porous articles and carefully dried to maintain their porous structure by such special techniques as freeze-drying or solvent drying. The resultant product is highly absorbent and is useful in such products as cigarette filters. Unfortunately, however, the extruded shapes are relatively hard, brittle and, when incorporated into a product such as a disposable diaper or a catamenial device, can cause discomfort to the user.